Explainer: What is thunderstorm asthma?

High pollen counts, warm weather and storms are the perfect conditions for thunderstorm asthma. Brandon LLW

If you suffer from itchy eyes, a runny nose, headaches and excessive sneezing this time of year, you’re certainly not alone. Hay fever or allergic rhinitis is an allergic reaction to pollen and affects one in six Australians.

But when you combine high pollen counts with thunderstorms and warm weather, a much more serious phenomenon can unfold: thunderstorm asthma attacks.

Grass pollen is usually too large to enter the small airways of the lungs and is filtered out by the nose, causing hay fever in those allergic to pollen.

But stormy winds and moisture can cause the pollen to rupture into tiny particles, which are small enough to be inhaled.

The outflow winds of a thunderstorm then concentrate these tiny particles at ground level, where they can easily enter the small airways of the lungs and cause an acute asthma attack in those who are allergic to grass pollens.

The symptoms of thunderstorm asthma can occur quickly and include shortness of breath, chest tightness, coughing and wheezing.

Stoms cause pollen to rupture into tiny particles, which can be inhaled into the lungs. Peet Sneekes